Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Well & Reservoir Surveillance and Monitoring
INTRODUCTION ABSTRACT This paper has numerically researched the effects of flow regime on particle trajectories as well as solids deposition behaviours in multiphase petroleum flow. In this study, the flow patterns frequently encountered in oil and wet-gas petroleum pipelines were targeted, including annular mist flow, stratified smooth/wavy flow, slug flow, and elongated/dispersed bubble flow. Distributions of the liquid-phase velocity in gas-liquid two-phase flow were determined by means of theoretical derivation, numerical simulation, or using commercial software. Based on the acquired liquid-phase velocity fields, particle velocities were calculated via Newton's second law. Subsequently, particle trajectories were tracked by solving the motion equation. Under an approximation of wall effect, the amount of solids deposition in multiphase petroleum flow was quantified. Furthermore, solids deposition behaviours with respect to solids/liquids properties, operating parameters, and pipeline terrain were characterized. Efforts were made to understand the solids deposition behaviours in multiphase petroleum pipelines which have been well known to initiate and accelerate localized pitting corrosion. This work was performed in conjunction with the ongoing development of our company's internal corrosion prediction model (ICPM) which is capable of predicting solids deposition as well as under-deposit pitting corrosion rate. Petroleum originates from the decomposition of organic substances under the effects of heat, bacterial action, pressure and other agents over long periods of time. During its formation, petroleum is surrounded by water trapped within the deposits such as sand, mud, clay and ooze of the ancient sea floor. Presently, about 70% of the total world's hydrocarbons are located in poorly consolidated reservoirs. Many reservoirs are susceptible to sand production. Inside petroleum pipelines, compounds carried by water as soluble constituents may precipitate and form scales as a result of pressure drop, temperature change, flow rate alteration, as well as pH variation. After being removed by mechanical or chemical methods, the corrosion production scales (FeCO3 and FeS) and the non-corrosion product mineral scales (S8, BaSO4, CaCO3, SrSO4, and CaSO4) will move along with the petroleum flow. Furthermore, poor filtration operations leave trace amounts of solid particles in the oil. These suspended solids and dissolved solids will likely settle on a metal surface if the liquid velocity is insufficient [1-5]. Accumulation of the settled solids shields the covered surface from the bulk system, leading to stagnant flow under the deposits. Infusion of ions from the bulk system into the shielded area and effusion of ions from the shielded solution into the bulk solution are diminished as a consequence of a negligible convection term. A concentration difference of specific ions and gases (e.g., chloride, oxygen) exists between the localized shielded area and the bulk solution. This can generate an anodic area under the deposits and cathodic areas at the leading edge encircling the anodic site, thereby setting up a basic corrosion cell. Due to electrochemical reaction, the metal at the anode is dissolved. Positively charged metal ions enter into the shielded solution. As the metal ions hydrolyze, hydroxyl anions are depleted, resulting in a reduced pH value under the deposits.
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
Erosion Corrosion And Synergistic Effects Under High Velocity Multiphase Conditions
Mori, Gregor (Christian Doppler Laboratory of Localized Corrosion University of Leoben) | Vogl, Thomas (Christian Doppler Laboratory of Localized Corrosion University of Leoben) | Haberl, Joachim (Christian Doppler Laboratory of Localized Corrosion University of Leoben) | Havlik, Wolfgang (OMV Exploration & Production GmbH Laboratory Materials & Corrosion) | Schöberl, Thomas (Department Material Physics University of Leoben)
INTRODUCTION ABSTRACT The present study has been conducted to investigate the interaction between erosion and corrosion processes under high velocity multiphase conditions. Tests were performed on martensitic stainless steel samples of grade UNS S42000. Pure erosion and pure corrosion as well as erosion corrosion impingement tests were carried out at three different impact velocities between 10 and 60 m/s. CO2 at a total pressure of 15 bar was used as the gas phase. The sand content, with grain size below 150 µm, was 2.7 g/L brine. Artificial brine with a NaCl content of 2.7 % at a gas liquid ratio of 20,000 (under standard conditions) was used as liquid phase. Damaged surfaces of specimens exposed to the high velocity multiphase flow were investigated by stereo microscopy, scanning electron microscopy (SEM) and an optical device for 3D surface measurements. Moreover electrochemical investigations according to ASTM G 61 were performed to determine electrochemical behavior of tested materials including critical pitting potentials Epit and repassivation potentials Erepass. Furthermore, near surface near regions of tested samples were investigated by applying nanoindentation in an atomic force microscope (AFM). Synergy effects as a function of impact velocity are quantified. At impact velocities of 10 m/s a pronounced synergistic effect of erosion plus corrosion was found, at high impact velocities this effect decreased due to domination of erosive damage. Erosion corrosion is a form of material degradation by simultaneous attack of erosion plus corrosion. It is clear that the mass loss rate by combined erosion corrosion is not simply the sum of erosion and corrosion mass loss rates. Instead of this some synergistic effects can occur. This is also valid for other mechanically influenced types of corrosion such as corrosion fatigue cracking (CFC) and stress corrosion cracking (SCC). Whereas under inert conditions there is a fatigue limit (at least for body centered lattices), this is not the case under CFC conditions. Degradation rates are increased in many cases when compared to pure fatigue or pure corrosive attack. SCC is actually a pure synergistic effect between mechanical load and corrosion since under pure and constant mechanical loads where SCC occurs the alloy is usually fully stable and under most SCC corrosive conditions the materials are still passive. So almost no degradation happens under single chemical or mechanical loads whereas catastrophic failures can occur under combined chemo-mechanical loads. Synergistic effects in erosion corrosion have been increasingly investigated by several authors in recent years since this is an important step to understand mechanistic phenomena in this highly complex material deterioration phenomenon. Neville and Souza looked fundamentally at the synergistic effects in erosion corrosion of WC-Co cemented carbide coatings by use of a two phase jet impingement cell with simultaneous electrochemical set up in 3.5 % NaCl at flow velocities of 17 m/s. Positive synergy effects were found to be between 0 and 40 % of total mass loss. Furthermore Neville et al. investigated a Stellite and an austenitic cast iron with the same methodology.
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
Corrosion And Erosion Corrosion Wear Resistance Of Rotating Components Made From Usn S43100 (1.4057) Steel Under Controlled Potentials
Klein, Oliver (Institute for Failure Analysis and Failure Prevention ISSV e.V., c/o Helmut Schmidt University) | Hoffmeister, Hans (Institute for Failure Analysis and Failure Prevention ISSV e.V., c/o Helmut Schmidt University) | Glafey, Alexander (Institute for Failure Analysis and Failure Prevention ISSV e.V., c/o Helmut Schmidt University)
INTRODUCTION ABSTRACT Rotating components in pumps are subjected to a high degree of wear when multiphase fluids containing corrosive elements as well as erosive particles are transported. The wear of these components leads to an increasing loss of efficiency and eventually to the failure of the pump. If the pump is to be used as a stand-alone system such as in ultradeep subsea applications in the oil and gas production industry, the wear has to be minimized. In this paper the wear resistance of USN S43100 steel as a rotating test sample with and without erosive particles in standardised formation water with CO2 is investigated at controlled potentials around the corrosion potential on both the anodic and the cathodic side. As a result it will be shown, that the metal loss of a rotating component is ten times higher than the metal loss of a identical, fixed component in the same environment. Furthermore it will be shown, that the corrosion potential is greatly influenced by the presence of erosive particles. In the case of anodic dissolution, pitting corrosion was found to be the prevalent cause for the metal loss. fluid phases such as oil with different viscosities as well as a chloride ion rich water phase, called formation water, gas phases, such as natural gas with different chemical compositions often containing carbon dioxide (CO2) and hydrogen sulphide (H2S) and solid phases such as sand and stones. Multiphase pumps (MPPs) have been used by the oil and gas production industry since the mid 1980s. They are used to boost the production flow line pressure in order to lower wellhead backpressures as illustrated in figure 1. This will not only allow for longer operational time, i.e. greater field recovery of a reservoir than would otherwise be possible, it also allows for a greater payoff in the initial stages of operation. As illustrated in figure 1, when booster pumps are installed downstream of production wells, the effect will be as if the wellhead pressures themselves were increased. The flow from the well will increase until a new balance between the production from the wells and the system resistance is achieved. The effect is a net increase in oil production.Although this technology is very adept at handling the transport of multiphase fluids without prior separation this process can, and in most cases will lead to the wear of pump components that are in contact with the transported medium due to the chemical and physical nature of the fluid mixture. The phases that can be encountered when transporting hydrocarbons areThe phases can be present in all possible volume factions depending on the nature of the reservoir and can also be subject to frequent changes as production commences. The multiphase pumps used by the industry for transport are either of rotodynamic or of volumetric design. Although there are a number of different pump types used in the industry.
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
A Two-Dimensional Mechanistic Model For Sand Erosion Prediction Including Particle Impact Characteristics
Zhang, Yongli (Erosion/Corrosion Research Center Department of Mechanical Engineering, The University of Tulsa) | McLaury, Brenton S. (Erosion/Corrosion Research Center Department of Mechanical Engineering, The University of Tulsa) | Shirazi, Siamack A. (Erosion/Corrosion Research Center Department of Mechanical Engineering, The University of Tulsa) | Rybicki, Edmund F. (Erosion/Corrosion Research Center Department of Mechanical Engineering, The University of Tulsa)
INTRODUCTION ABSTRACT The design of oil and gas production equipment to withstand erosive conditions and optimize the production rate, while keeping the piping system operating safely, requires a reliable erosion prediction tool. It is well known that many factors can affect erosion damage, such as flow geometry, pipe material, carrier fluid properties, flow conditions and flow regime, and particle properties. To predict erosion, a key ingredient is to have properly calculated particle impact parameters, such as impact velocity, impact angle, impact location, and impact frequency. The guideline in API RP 14E is not reliable in determining erosional threshold velocity when sand production is expected. A few models that were previously presented in the literature to calculate solid particle erosion utilize the fluid velocity instead of the actual particle impact velocity. These models account for fluid density, particle diameter, and some common flow geometries, and have been compared with some lab and field data. Their application, however, is limited due to the limited physics behind them. Shirazi et al. presented a mechanistic model accounting for most of the key parameters listed above. This model predicts erosion rate using the calculated representative particle impact velocity. The drawback of this previous model is that the calculation is based on one-dimensional particle tracking. This limits its application to relatively large sand particles (>50 to 100 microns) or cases where gas is the carrier fluid. After extensive studies utilizing CFD-based erosion modeling, the authors found that both the normal and tangential particle impact velocity components and the turbulence field are essential in erosion calculations for certain cases. A mechanistic model based on two-dimensional particle impact characteristics was developed based on these findings. Comparisons of results from the 2-D mechanistic model and the previous 1-D model together with the CFD-based model, and experimental data are presented in this paper. In the oil and gas industry, in order to design equipment to withstand erosive conditions or to optimize the production rate while keeping the piping system operating safely, a reliable erosion prediction tool is necessary. A wide variety of erosion prediction methods have been proposed by many investigators. These methods are either based on some experimental data or just accumulated field experience. Some professional tools developed by some research institutes are also available. But unfortunately, many of these models are based on empirical information, thus limiting their applicability to a wide range of flow conditions. A guideline that has been widely used in industry is the American Petroleum Institute (API) Recommended Practice 14E (API RP 14E). According to this guideline, less erosion is anticipated for a less dense fluid. But, this has been shown not to be true experimentally. Also, this guideline does not account for many factors affecting erosion, such as particle rate and properties, wall material mechanical properties, impact particle velocity and pipe flow geometry. Salama and Venkatesh proposed an alternate correlation to API RP 14E.
- Well Completion (1.00)
- Reservoir Description and Dynamics (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers (1.00)
Sand Erosion In Multiphase Flow For Slug And Annular Flow Regimes
McLaury, Brenton S. (Department of Mechanical Engineering The University of Tulsa) | Shirazi, Siamack A. (Department of Mechanical Engineering The University of Tulsa) | Rybicki, Edmund F. (Department of Mechanical Engineering The University of Tulsa)
INTRODUCTION ABSTRACT Erosion in multiphase flows, with entrained sand, is a more complex phenomenon than erosion in single-phase flow because of the different flow regimes possible. Earlier predictive models for erosion in multiphase flow were primarily based on empirical data and the accuracy of those models was limited to the flow conditions of the experiments. A mechanistic model has been developed for predicting erosion in elbows in multiphase flow considering the effects of particle velocities in gas and liquid phases upstream of the elbow. Local fluid velocities in multiphase flow are used to calculate erosion rates in multiphase flow using particle tracking and erosion equations. Because the mechanistic model is based on the physics of multiphase flow and the erosion phenomenon, it is expected to be more general than the previous empirical models. Erosion experiments were conducted on two-inch and three-inch elbows in a large scale multiphase flow loop with gas, liquid and sand for gas and liquid velocities producing slug and annular flows. The annular flow experiments were primarily performed in the upward vertical orientation but a few experiments were performed in the horizontal orientation. All the slug flow experiments were performed in the horizontal orientation. Based on the experiments, the mechanistic model has been improved to predict erosion in several different multiphase flow regimes considering the effects of sand particle distribution and particle velocities in gas-liquid flows. Transporting liquids and gases simultaneously is a necessity for many industrial applications, and dealing with a gas-liquid flow results in many challenges. The addition of particulates to a gas-liquid flow complicates the issue further resulting in additional concerns and uncertainties. If gas and liquid flow rates are relatively low then the particles may settle and accumulate in horizontal runs. On the other hand, if flow rates are relatively high then erosion of the piping or tubing can occur. Erosion is most severe when particles are transported in gas dominant systems. Typically, the flow velocities are much higher and the fluid density is less resulting in high velocity impacts of solids. Two multiphase flows that contain significant gas that can result in severe erosion are annular and slug flow. The presence of liquid generally decreases the erosion rate for a given gas rate. However, erosion does not consistently decrease with an increase in liquid rate for a given gas rate. In fact, for certain ranges of liquid rates, the erosion rate can increase with an increase in liquid rate for a given gas rate. This behavior can occur in annular flow. The goal of this work is to present a mechanistic approach to predict the erosion rate in annular and slug flows with solid particles that accounts for gas, liquid, and solid properties and rates. BACKGROUND Many aspects of erosion have been studied for decades. However, models developed specifically for oil and gas production are few, and models for erosion prediction in annular flow are even scarcer.
- North America > United States > Texas (0.46)
- North America > United States > Gulf of Mexico > Eastern GOM (0.24)
- Reservoir Description and Dynamics (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
Erosion Of Austenitic Stainless Steel 90° Elbows Of Charge Heater Tubes In Atmospheric Residue De-Sulfurization Unit (Ards)
Al Arada, Muased (Kuwait National Petroleum Company Mina Abdulla Refinery) | AL-Enezi, Mutlaq M. (Kuwait National Petroleum Company Mina Abdulla Refinery) | Vipat, Sunil V. (Kuwait National Petroleum Company Mina Abdulla Refinery) | Ray, Anil Kumar (Kuwait National Petroleum Company Mina Abdulla Refinery)
ABSTRACT Charge heater radiant and convection coils (tubes, U-bends & 90° radiant outlet elbows) in Atmospheric Desulfurization Unit (ARDS) of Mina Abdulla Refinery are made up of TP 347SS material. Charge heater is used for heating of atmospheric residue prior to entering into ARDS reactors for further desulfurization / de-metallization. Severe erosion and thinning was observed in the 90° radiation elbows during Year 2002 shutdown after a service life of about 12 Years. Erosion was noticed in charge heaters H-12-101 & H-12-201 in both ARDS Trains. These radiation 90° elbows are outside the charge heater firebox upstream of the heater outlet header. This particular erosion phenomenon was restricted to a small area of the 90° elbows and resembled a sharp knife-like attack at the point of maximum damage. The most probable reasons for such severe erosion was the impingement of coke particles at the outer radius during online spalling and steam/air decoking operation during which velocities of steam/air may reach a very high magnitude. The high velocity steam/air stream carrying coke particles causes a bullet like impact on the point of incidence and the metal thereof is removed causing erosion. INTRODUCTION Atmospheric Residue Desulfurization (ARDS) is a well established hydro treating process, operated primarily to desulfurize atmospheric residues from Crude units and to prepare feed stocks for downstream conversion units like Hydrocrackers and Delayed Coker units. The product, desulfurized residue, is not only low in sulfur but has improved pour points and lower viscosities as well. In addition to existing ADRS technology, ARDS unit was revamped with OCR (On-Stream Catalyst Replacement) Technology in September 2004 to achieve a more efficient desulfurization. After the revamp of ARDS Unit with On-Stream Catalyst Replacement facility, operating capacity of the unit is now 84,000 BPOD against original capacity of 66,000 BPOD. Reduced Crude/Atmospheric Residuum (AR) Feed. Make Up Hydrogen Compression Reaction On-Stream Catalyst Handling Distillation Revamped ARDS Unit consists of five principal systems:(Figure in full paper) To achieve deep desulfurization, the heated feed oil is mixed with hydrogen-rich recycle gas downstream of the charge heaters and passed over a series of one On-Stream Catalyst Replacement Reactor and four fixed bed reactor beds at high temperature and pressure. In this process, AR Feed first flows in to On-Stream Catalyst Replacement reactor where major fraction of feed metals are removed by catalytic hydro-demetalization and 40% to 50% of the sulfur compounds are converted to H2S via catalytic hydro-desulfurization. The mixture then flows to the fixed bed reactors where more difficult sulfur compounds are converted to H2S and some of the remaining feed metals are converted to metal sulfides. The feed contaminants such as sulfur, nitrogen and metals are reduced and oxygen compounds and organic chlorides are converted. Mild hydro cracking leads to production of lighter products. These reactions are highly exothermic and consume hydrogen. After the reactions, the effluent mixture is cooled and separated in to gas and oil phases, in different stages of high and low pressure separators.
- Reservoir Description and Dynamics (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (0.69)
- Facilities Design, Construction and Operation > Processing Systems and Design > Separation and treating (0.54)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (0.46)